The present invention relates generally to medical products and procedures. More specifically the present invention relates to containers for storing medical solutions and methods of sterile admixing such solutions before they are administered to a patient.
It is of course known to store medical solutions in containers. A variety of such solutions are housed and stored in such containers. Such medical solutions can include, for example, parenteral, enteral, dialysis solutions, nutrients and pharmacologic agents, including gene therapy and chemotherapy agents.
These containers can be either constructed from glass or plastic. Plastic containers can either be rigid or flexible. Flexible containers are constructed from plastic films.
Although there are a great variety of solutions that are used in medical treatments today, there are however, a number of issues that can limit the ability to store at least certain medical solutions. For example, due to stability, compatibility or other concerns a number of medical solutions can not be premixed. Rather, the individual components must be stored separately. Typically these components are either stored in separate containers and admixed before use, or are stored in separate compartments of a flexible container and then mixed prior to use. For example, amino acids and dextrose solutions require storage in separate containers or compartments.
One of the disadvantages of storing components in separate containers and then mixing them together is that the mixing process can compromise sterility of the system and/or process. Additionally, such a mixing process creates a labor intensive process. Still further, it is possible for mistakes to occur during the admixing process due to the amount of solution to be added from the separate containers into the final container for the patient.
To deal with the disadvantages of separate containers, it is known to provide flexible containers that include multiple chambers. To this end, such containers have an interior that defines two or more chambers. One way to create such a container is with a heat seal that divides the interior into two chambers. Such containers are disclosed, for example, in U.S. Pat. Nos.: 4,396,488; 4,770,295; 3,950,158; 4,000,996; and 4,226,330.
It is also known to use frangible valves between the heat seal to allow for the selective communication and mixing of the two components stored in the separate chambers. See, for example, U.S. Pat. No. 4,396,488.
However, such a structure-frangible valves—may not be desirable for a number of reasons, including, inter alia, mixing time, particulate matter generation, difficulty in opening, difficulty in achieving a homogenous mixture, and cost. An alternative to frangible valves is disclosed in U.S. Pat. Nos: 3,950,158; 4,000,996; and 4,226,330. In these patents multiple chamber containers are disclosed with a line of weakness, such as a score line, which breaks upon the application of pressure.
U.S. Pat. No. 4,770,295 discloses a selectively openable seal line positioned between two sheets of flexible thermoplastic material. The seal line is resistant to unintentional opening forces but opens upon the application of a specific force.
Additionally, it is known to use tear tabs or tear strips for plastic containers. See U.S. Pat. Nos.: 2,991,000; and 3,983,994. A disadvantage of these systems is they involve the use of relatively complicated seal structures.
A number of other issues must also be addressed in constructing containers for use in the medical industry. For example, it is typically necessary to sterilize the container and solution after manufacturing the container and solution. Typically the products are sterilized by steam sterilization or autoclaving. Autoclaving sterilization can alter the thermal properties of the film used to form the container as well as the seal between the chambers in the container. Still further heat sterilization can adversely effect the solutions contained therein unless they are maintained at certain conditions, an example of such a composition is dextrose.
Of course, it is necessary that the seal between any multiple chamber container is able to withstand external stresses. Such stresses can include pressure that may be applied to one or more of the chambers from, for example, squeezing thereof or accidentally dropping the bag. Therefore the seal must be sufficiently strong. But, on the other hand, the seal must not be too strong so that it is not possible to mix the solutions contained therein before one intends that they be mixed.
Still further, a problem that one faces, especially with respect to parenteral nutritional solutions, is that the components that comprise the solutions may not only not be compatible with each other but, also may not be compatible with the materials from which the container is constructed. For example, lipids cannot be housed in typical plastic materials used to make containers. Lipids can leach certain materials out of the plastic; if a lipid is housed in a polyvinyl chloride material it will leach out the plasticizers. Leaching of the plasticizer causes toxicity issues. Additionally, when the plasticizers are leached out, the plastic becomes rigid. Therefore, heretofore commercially available lipid products only have been housed in glass containers.
One form of potentially life supporting therapy is total parenteral nutrition or hyperalimentation. Typically, parenteral nutrition solutions that provide total nutritional requirements to a patient include a lipid component, a carbohydrate component, a protein component, and vitamins and minerals.
Because of a number of stability and related issues, total parenteral nutrition solutions can not be stored in a ready to use state. Thus, it is necessary to admix the solutions prior to use.
Heretofore, due to the inability to store all the base components that may be necessary for a parenteral nutritional solution in a single container, it is known to use automated compounders for admixing parenteral nutritional solutions. In such compounders, solution containers are hung on the compounder, and through the use of pumps or valves the solutions therein are compounded to create a final solution including all of the necessary components, e.g. lipids, carbohydrates and amino acids. U.S. Pat. Nos. 4,653,010, and 4,467,944 disclose embodiments of such automated compounders.